console.log(NaN == NaN,
	NaN === NaN,
	Object.is(NaN, NaN),
	0 == -0,
	0 === -0,
	Object.is(0, -0),
	null == undefined,
	null === undefined,
	Object.is(null, undefined));
let a, b;
console.log(Object.is(a, b));
